1. Field of the Invention
The present invention relates to a method to remove glass particles deposited on the inner wall of a glass injection syringe and more particularly, to a method to completely remove glass particles produced during a manufacturing process and later adhered to the inner wall of a glass injection syringe thus being mistakenly injected into the bloodstream of a human body.
2. Description of the Prior Art
There are various types of injections (e.g., ampules, vials, bottles, etc.) classified according to the containers into which each injection is inserted. In general, injection containers are made of either glass or plastic and glass is often more preferred.
The way each injection is prepared varies depending on the container of each injection material. For example, ampule-type injection containers usually produce a lot of broken glass particles when severed by medical operators to prepare injections while vial-type containers often produce broken rubber fragments when a reciprocating movement is performed a few times to suck a given pharmaceutical liquid. The problems of inconveniences in medical practices and the environmental contamination resulted from using the above injection containers have been much resolved since the introduction of `prefilled syringe`. The prefilled glass syringe, being prefilled with a certain pharmaceutical liquid, can easily deliver the injection through a patient's blood vessels or muscles without much difficulties; however, it also had the drawback of not being able to prevent minute glass particles adhered to the inner wall of a glass injection syringe from being injected along with prefilled pharmaceutical liquid because the injection liquid gets flowed into a person's bloodstream by a pushing force of a rubber plunger of a syringe which is in close contact with the inner wall of the syringe.
In producing glass injection syringes, minute broken glass particles are generated during a process of cutting off glass tubes at appropriate lengths by using a flame and also a finishing process of forming a crown. The glass particles produced and then scattered around the inner wall of a syringe and finally become stuck to the inner wall of a syringe during a subsequent heat treatment. The above syringes, upon completion of production, are placed to go through with a series of rinsing steps to wash off all the other remaining impurities as well as glass particles adhered to the inner wall of a syringe by utilizing methods such as an ultrasound rinse, an unsaturated ammonium rinse, a TAO neutralization and a purified water rinse, a diluted HCl rinse, a surfactant rinse; however, said glass particles are most of the time hardly removed.
The conventional methods of rinsing a glass syringe are described hereunder.
1) Spray pressed air into the inner wall of a glass syringe with the air pressure of 6-7 kg/cm.sup.2. (Unable to remove glass particles.) PA0 2) Add surfactants into an ultrasound rinsing equipment, rinse the glass syringes for 4 hrs and finally rinse with purified water. (Unable to remove glass particles.) PA0 3) Immerse said glass syringes in 50% acryl #25, a surfactant, for 2 hrs and then rinse them in an automatic washer at water pressure of 6 kg/cm.sup.2 and air pressure of 7 kg/cm.sup.2. (Unable to remove glass particles.) PA0 4) Sterilize with steam water at high temperature of 121.degree. C. for 45 min and then rinse with water and air under the pressure of 6 kg/cm.sup.2 and 7 kg/cm.sup.2 respectively. (Unable to remove glass particles.) PA0 5) Immerse said glass syringes in diluted HCl for 2 hrs and rinse. (Unable to remove glass particles.) PA0 6) Reciprocate with a silicon-rubber plunger made properly fit into the inner wall of a glass syringe. (Unable to remove glass particles because the diameter of the inner wall of each syringe is not usually uniformly made throughout the inner channel of the entire cartridge.) PA0 7) Reciprocate with a sponge plunger made properly fit into the inner wall of a glass syringe. (Unable to remove glass particles because the sponge plunger is neither durable nor practical.) PA0 8) Reciprocate with a wool brush. (Can remove large glass particles and other impurities but unable to remove minute glass particles.) PA0 9) Reciprocate with a stainless steel wire brush. (Unable to remove minute glass particles and also produces scratches on the inner wall of a syringe.)
In general, the glass particles are of various sizes ranging from 3-60 .mu.m or above. Particles with a size smaller than 30-50 .mu.m are invisible to the naked eyes and thus have to be examined by using an automatic impurity detector. However, the above equipment is designed to detect only moving particles and is not suitable to detect glass particles that are adhered to the inner wall of a syringe. In the above-mentioned prefilled syringes, the glass particles adhered to the inner wall of a syringe and smaller than 40 .mu.m, which is approximately the same size of the inner diameter of an injection needle, will be immediately delivered into a human body along with a pharmaceutical liquid during an injection and cause a variety of serious side-effects when accumulated in a reticuloendothelial system such as liver, spleen and lungs. Thus it is highly urgent to find out a solution to prevent patients from being kept vulnerable to medical malpractice.